Case study · AI / Voice

Malagasy speech recognition.

A model trained by Sooatek for the short utterances of a voice assistant, measured on speakers never heard in training, and published openly with its figures.

Client Sooatek project, public Updated on

Context, constraint, solution, outcome.

01 Context

Malagasy is a low-resource language: little annotated data, and speech recognition models trained and measured mostly on 15 to 30-second recordings. A voice assistant, however, receives short utterances.

02 Constraint

Measure honestly: 11,625 utterances of 2 to 8 seconds, spoken by 94 speakers absent from training, text normalized on both sides, each gap checked statistically (paired bootstrap, 95%).

03 Solution

A w2v-BERT 2.0 model fine-tuned from a public model and also trained on short utterances, a Malagasy language model, a separate model that restores casing and punctuation, and a version that runs on a CPU.

04 Outcome

  • 12.7% word error rate on short utterances (with a language model; 14.3% without), against 21.5% for our previous model, a Whisper medium fine-tuned on the same data.
  • 10.1% on full-length clips: no regression on complete recordings.
  • 52 ms median latency per utterance on a GPU, against 259 ms for the Whisper medium.

What was delivered.

  • Speech recognition model, under the CC-BY-4.0 license
  • Malagasy language model
  • Casing and punctuation restoration model
  • CPU version, no graphics card needed
  • Online demo, usable in the browser
  • Public model card: protocol, measurements and limitations

Architecture, in principle.

Conceptual diagram: from voice to punctuated text A short utterance is transcribed by the fine-tuned w2v-BERT 2.0 model, helped by a Malagasy language model; a second model then restores casing and punctuation. Conceptual diagram, simplified

What we take away.

  • Measure in real-use conditions: on this corpus, existing models make noticeably more errors on short utterances than on long recordings.
  • We publicly corrected a wrong measurement of our previous model (text not normalized): that model’s card says so and points to the new one.

Check for yourself.

Figures and method are public. Links to external pages.

Related offer.

Does your business have its own language, vocabulary or images? We adapt a model to your data, measured before and after.

Offer 08

6 to 10 weeks

Specialized AI model

A model adapted to your language, vocabulary or images, measured before and after: fine-tuning, speech, vision.

Included

  • Data audit and preparation
  • Training, evaluation on an unseen set
  • Delivery for server, CPU or phone
  • Measurement report

Pricing

Fixed price, on quote

GPU compute re-invoiced at actual cost

Written by

Florent Didelot, principal

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